This subsection briefly reviews the results in [1]} relevant to sectional curvature. The authors defined a general right-invariant metric on SU\((2^N)\) . The metric components in the Hamiltonian representation is given by
\((H|J)_{\mathcal {C}}\equiv (H|\mathcal {G}|J)=2^{-N}\textrm {Tr}(H\mathcal {G}(J)).\) 
